The Raglan opens at 4 pm on weekdays other than Friday I think when it's open all day.
The Alex has improved since being taken over by the owners of The Vic who also run the Atomic brewery from The Alex.
The Duck tends to have between 2 & 4 beers on generally from either nationals or large regionals. As to quality I haven't had an issue there but don't frequent it regularly as there are too many other decent boozers.
I haven't been in The Half Moon recently but it's still regularly used by a number of ale drinking friends with few complaints.
The London is a Marstons house which has long had a reputation for decent Pedigree. I didn't know it was known as Rugby's roughest pub, although there isn't huge competition for that title, so maybe a daytime visit would be most sensible or avoid it as there are plenty of others.